George Russell claims he endured “a mind-boggling weekend” in São Paulo which he feels has left Mercedes facing “so many question marks”.

Russell and team-mate Lewis Hamilton were miserably off the pace in the sprint and grand prix at Interlagos, just a year after the younger Briton won both events, spearheading a one-two in the main race as the seven-time F1 champion finished runner-up.

In the sprint on this occasion, Russell finished 25 seconds adrift in fourth behind winner Max Verstappen in his Red Bull, before retiring on Sunday due to rising temperatures in the power unit.

Even prior to that, however, Russell was struggling, whilst Hamilton drifted back through the field, finishing eighth and just over a minute behind Verstappen.

Team principal Toto Wolff described the weekend personally as his “worst in 13 years” in the sport.

“A mind-boggling weekend to understand,” remarked Russell, who has only finished on the podium once this season, in contrast to his eight podium appearances last year, including the win in Brazil.

“We had relatively high expectations coming into the weekend, but just absolutely no pace at all, and yet it’s been the same car as the last five races, so clearly there was something wrong.

“And in a sprint race weekend, when you get it wrong, you can’t make amends with those issues.”

Mercedes notably struggled with top speed, with the W14 amongst the slowest on the straights, which Russell concedes left him “a sitting duck”.

Despite the team running more downforce, he added: “When you run more downforce you’re meant to gain the speed through the corners, keep the tyres under control, and that wasn’t the case, so we didn’t have the benefit we only had the negative.”

Before São Paulo, Mercedes appeared to have taken steps forward, notably with the introduction of a new floor ahead of the United States GP in Austin.

Hamilton finished second in that race – although was subsequently disqualified due to his car sustaining excessive skid block wear – before again taking the runner-up spot in Mexico City

“It’s so many question marks,” said a concerned Russell. “As I said, it’s the exact same race car as we’ve had since Austin.

“The car has been capable of podiums at every race, even before then in Singapore, Qatar, it was capable of podiums.

“This is clearly a substantial one-off event but we need to understand what we got wrong.”